Sharpening device for lawn mowers



March 9, 1948. A. SPORKET 2,437,443

SHARPENING DEVICE FOR LAWN MOWERS Filed Oct. 18, 1945 v fve 7 07" Patented Mar. 9, 1948 UNITED STATES PATENT OFFICE 2,437,443 SHARPENING nEvIdE roa LAWN miowsas Albert Sporket, Detroit, Mich.

Application October 18, 1945, Serial No. 623,112

7 Claims. 1

This invention relates to sharpening devices, and in particular, to devices for sharpening the blades of lawn mowers.

One object of this invention is to provide a readily attachable and detachable device for lawn-mowers wherein abrasive is automatically supplied to the cutter bar and reel blades so as to sharpen them by their interaction as the lawn mower is pushed along a smooth surface such as a cement floor or sidewalk.

Another object is to provide a blade sharpener for lawn-mowers as set forth in the preceding object wherein the abrasive is in the form of a paste arranged in pockets in an attachable member which is engageable with the reel blades.

Another object is to provide a blade sharpener for lawn-mowers wherein an attachable curved member having wedge-shaped pockets filled with abrasive paste is covered by a screen whereby the contact of the reel blades with the screen presses the latter into the pockets and causes abrasive to be pressed out onto the screen and thence transferred to the reel blades, which then sharpen themselves by a lapping action relatively to the cutter bar of the mower.

Another object is to provide a sharpening device for lawn-mowers as set forth in the preceding objects wherein the device is detachably secured at its lower side to the cutter bar and at its upper side to a cross rod of the mower, with spring preferably provided for urging the abrasive carrying member into yielding engagement with the reelblades.

Other objects and advantages of the invention will become apparent during-the course of the following description of the accompanying drawing, wherein:

Figure 1 is a top plan view of the forward end of a lawn-mower showing the sharpening device of this invention attached thereto;

Figure 2 is a vertical cross-section along the line 2-2 in Figure 1;

Figure 3 is a perspective view of the sharpening device detached from the mower, with a portion of the screen broken away to disclose the abrasive pockets; and

Figure 4 is an enlarged fragmentary cross section through one of the abrasive pockets.

Referring to the drawings in detail, Figure 1 shows the forward end of a lawn-mower, generally designated l0, having wheels H supported upon end frame plates l2 which are interconnected by a tie rod [3 and reel shaft I4. Extending rearwardly from the end plates i 2 are arms l5 having a cross bar l8 extending therebetween. 4

cutter bar I1, the whole being adjustable up or down by means of the screws i8 and [9 (Figure 2) and the upwardly projecting fulcrums engaging correspondingly concave notches 2| in the brackets 22 attached to the cross bar 16.

Mounted on the reel shaft l4 are spiders 23 carrying the usual spiral reel blades 24, the entire assembly constituting the reel 25. The reel shaft I4 is rotatably connected to the wheels I! in the usual way with a pawl and a ratchet drive (not shown) so that the reel 25 rotates when the lawn-mower I0 is pushed forward and re mains stationary when it is pulled backward.

The sharpening device 2-5 (Figure 3) consists of a curved sheet member 21 of metal or other suitable material having secured thereto a similar sheet member 28 provided with apertures 29 v forming pockets in cooperation with the sheet member 21. The pockets 29(Figure 4) taper toward their forward edges so as to be shallower or wedge-shaped. Mounted over the aperture sheet member 28 is a netting member 30, the members 21, 28 and 36 being held together by the bar 3| and rivets 32. I

The sharpening device 26 is provided with curved bars 33 having wires 34 for securing them and the sharpening device 26 to the tie rod i3. The lower ends of the bars 33 are riveted as at 35 to the sheet members Zl and 28 and the netting member 38, and forwardly of this are provided with bent portions 35 having holes 37 therein. Extending through the holes 3'! are wires 38 connected as at 39 to hooks 4!! adapted to slip over the rearward edge 4! of the cross bar 16 of the cutter bar H. The other ends of the wires 38 are connected as at 42 to tension springs 43 having their upper ends connected to the curved bars 33, as at the rivets 32.

In the operation of the invention. when it is desired to sharpen the lawnmower ID, the hooks 4!! are slipped over the rearward edge 4| of the cross bar l6 and the Wires 34 twisted around the tie rod l3, so as to hold the sharpening device 26 firmly in contact with the reel blades 24. The pockets 29 have been previously filled with paste containing an abrasive.

To sharpen the blades, the mower is now pushed along a floor, walk or pavement so that the reel 25 revolves. As it does so, the reel blades 24 sweep past the sharpening device 25, pressing the netting 38 into the abrasive paste 44 in the pockets 29 and causing some of the paste to be pushed through the netting 30 to the outside thereof. There it is picked up by the blades 24 and car- While I have shown and described my invention in detail, it is to be understood that the same is to be limited only by the appended claims, for many changes may be made without departing from the spirit and scope of my invention.

What I claim is:

1. A sharpening device for lawn-mowers having a bladed cutting reel, a cutter bar and a tie rod interconnecting the end plates and wheels respectively, comprising an elongated member of concavely curved cross-section engageable with the cutting reel blades and having pockets therein, loose abrasive means mounted in said pockets, and connectors extending between said member and said lawn-mower for attaching said member with said means in contacting engagement with said reel blades.

2. A sharpening device for lawn-mowers having a bladed cutting reel, a cutter bar and a tie rod interconnecting the end plates and wheels respectively, comprising an elongated member of concavely curved cross-section engageable with the cutting reel blades and having pockets therein with bottom portions tapering toward their tops, loose abrasive means mounted in said pockets, and connectors extending between said mem bar and said lawn-mower for attaching said memher with said means in contacting engagement with said reel blades.

3. A sharpening device for lawn-mowers having a bladed cutting reel, a cutter bar and a tie rod interconnecting the end plates and wheels respectively, comprising an elongated member of concavely curved cross-section engageable with the cutting reel blades and having pockets therein with bottom portions tapering toward their tops in the direction of rotation of said reel blades, loose abrasive means mounted in said pockets, and connectors extending between said member and said lawn-mower for attaching said member with said means in contacting engagement with said real blades.

4. A sharpening device for lawn-mowers having a bladed cutting reel, a cutter bar and a tie rod interconnecting the end plates and wheels respectively, comprising an elongated member of concavely curved cross-section engageable with the cutting reel blades and having loose abrasive portions thereon, a reticulated element disposed between said elongated member and said reel blades and connected to said elongated member, and means for attaching said member to said lawn-mower in contacting engagement with said reel blades.

5. A sharpening device for lawn-mowers having a bladed cutting reel, a cutter bar and a tie rod interconnecting the end plates and wheels respectively, comprising an elongated member engageable with the cutting reel blades and having an approximately cylindrical concave portion on one side thereof, loose abrasive portions associated with said cylindrical portion, a reticulated element disposed between said abrasive portions and said reel blades and connected to said elongated member, and means for attaching said member to said lawn-mower in contact- .ing engagement with said reel blades.

6.1n a sharpening device for lawn-mowers having a bladed cutting reel, a cutter bar and a tie rod interconnecting the end plates and wheel respectively, comprising an elongated member of concavely curved cross-section engageable with the cutting reel blades and having pockets therein, loose abrasive means mounted in said pockets, a reticulated element mounted over said pockets and disposed between said elongated member and said real blades and connected to said elongated member, and connectors extending between said member and said'lawnmower for attaching said .member with said means in contacting engagement with said reel blades.

'7. In a sharpening device for lawn-mowers having a bladed cutting reel, a cutter bar and a tie rod interconnecting the end plates and wheel respectively, comprising an elongated member of concavely curved cross-section engageable with the cutting reel blades and having pockets therein with bottom portions tapering toward their tops in the direction of rotation of said reel blades, loose abrasive means mounted in said pockets, a reticulated element mounted over said pockets and disposed between said elongated member and said reel blades and connected to said elongated'member, and connectors extending between said member and said lawn-mower for attaching said member with said means in contacting engagement with said reel blades.

ALBERT SPORKET.

REFEEENCEE CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,124,900 Hineman Jan. 12, 1915 1,191,160 Davidson July 18, 1916 2,23%,764 Schneider Feb. 4, 1941 2,343,072 Miller Feb. 29, 1944 

